Automatic lock bottom carton



p 1 1.. H. PHILLIPS 2,569,335

' AUTOMATIC LOCK BOTTOM CARTON Filed June 9, 1949 2 Sheets-Sheet 1 1 Q Y721/8 nfor: J 2:6 LawrerzceHPhiZZr ps Sept. 25, 1951 A L. H. PHILLIPS 9,

AUTOMATIC LOCK BOTTOM CARTON Filed June 9, 1949- 2 Sheets-Sheet 2 I EQy-WA Mm/U Patented Sept. 25, 1951 UNITED s A Es PATENT. OFFICE AUTOMATIC LOCK BOTTOM CARTON Lawrence H. Phillips, Chattanooga, Tenn., assignorto 0. B. Andrews Company, Chattanooga, Tenn., a corporation of TennesseeApplication June 9, 1949, Serial No. 98,103

2 Claims.

The present'invention relates to an automatic lock bottom carton, a typeof carton having a bottom so constructed that itselements lie betweenthe Walls of the container in its collapsed state and are automaticallymoved to closureforming position and locked upon spreading of the wallsto set up the container. The invention relates especially to a positive,non-jamming lock for such a carton.

Such cartons are furnished in flattened or collapsed condition, foreconomy and convenience in shipment and storage, and are set up to thedesired container form when the contents are to be inserted.Particularly in cases where smooth, rapid flow of a packing line isdesirable, but also in smaller-scale operations, it is important thatthe cartons be easily and rapidly set up, but it is even more importantin avoiding costly delays that each and every carton set up properly,and that it be positively locked in set up or erected condition. Thatis, each setting up operation must result in a fully erected cartonwhich is positively prevented from collapsing. Automatic lock bottomcartons of prior constructions have sometimes failed in these respectsbecause the elements of the bottom have jammed during the erectingoperation, or because the locking elements have not actually engagedsufliciently to prevent collapse of the carton although it might remainerected temporarily.

The carton of the present invention is constructed of folding boxboardor other suitable sheet material with looking tongues so disposed on themain bottom panels and having locking edges so formed that they will bepositively pre- 1 moved to locking position as the carton is brought toerected condition. Each setting up operation therefore results in aperfectly set up and positively locked carton.

The construction andoperation of the carton of this invention areexplained and the principles made clear in the following description ofone embodiment of the invention, reference being had to the accompanyingdrawings, in which:

Fig. 1 is a view of the interior of a carton embodying the invention,showing the position of the-bottom parts at one stage of the setting upof the carton, as seen from above the carton;

Fig. 2 is a view showing the parts in the same position as in Fig. l asseen from below the carton;

Fig. 3 is a view similar to that of Fig. l, but

at the final or locked stage of the setting up operation;

Fig. 4 is a view similar to that of Fig. 2, but

I showing the parts in the final or locked position;

Fig. 6 is a plan view of the blank of Fig. 5 partly folded; and

Fig. '7 is a view of the carton in collapsed condition resulting fromcompletion of the folding and gluing of the blank of Fig. 5.

'Referring to the drawings, the carton I0 is formed from the blank I Ishown in Fig. 5, which comprises side wall panels I2 and I3 seriallyalternated with end wall panels I4 and I5, one of the terminal panels,in this case panel I2, having hinged thereto a securing flap I6. Hingelines I1, I'la, Ill), and He define the panels. A bottom panel I8,having a width half that of the carton, is hingedly connected to thebottom edge of the side wall panel I 2, and has a tongue I9 extendingfrom its free edge substantially centrally thereof. A bottom panel 20 ofthe same width as the panel I ILis hinged on the bottom of the otherside wall panel I3, and has extending from its free edge a pair oftongues 2| and 22, with their inner ends spaced apart a distancecorresponding substantially to the length of the tongue I9. Each of theend wall panels I4 and I5 has hinged to itsbottom edge a bottom flap 23.which is divided into. a triangular portion 24 and a securing portion 25by a fold line 26. The panels I8 and 20 are preferably of substantiallythe same length as the panels I2 and I3, and may have their ends 21adjacent the securing portions 25 substantially in alignment with scorelines Ila and We, as shown, or cut away at a slight angle to reduceinterference with the adjacent end wall during the setting up operation.Each of the tongues I9 and 2| has formed on its end adjacent or directedtoward the securing portion 25 of the adjacent flap 23, that is, itsright-hand end as viewed in Fig. 5, a locking edge 28. The locking edges28 are formed to extend perpendicularly relative to the bottom edges ofthe side walls I2 and I3. The corners of the tongues may be rounded ifdesired, but not sufficiently to substantially eliminate the lockingedges 28 as described.

The carton I0 in collapsed tubular condition is formed from the blank IIby first folding the bottom panels and flaps over their respective wallpanels and folding the securing portions 25 back upon the portions 24 ofthe flaps, as shown in-Fig. 6. Adhesive 29 is applied to appropriateareas, for example as shown in Fig. 6, and the blank then folded on thelines Ila and Ilc. The carton then is complete, in the collapsedflattened form shown in'Fig. 7. The folding and gluing of the blank maybe accomplished by any suitable means, and may be performed somewhatdifferently than as described, as will be clear to those skilled in theart. Al'- though adhesive is preferred as the means for securing theparts of the carton, other securing means may, of course, be employed.

In the flattened condition of the carton shown in Fig. '7, the bottompanels l8 and 20 lie against the walls I2 and I3, respectively, and eachof the flaps 23 in its reversely folded condition is disposed betweenthe end wall on which it is hinged and one of the bottom panels. Thesecuring flap l6 may lie on either the inside or outside of the carton,as desired, but as shown is on the inside.

In erecting the carton I0, it is only necessary to apply pressure to thefiat collapsed form just described at the ends thereof, defined by thehinge lines I10. and Ho, as indicated by the arrows in certain of thefigures. This moves each of the walls l2, l3, l4 and I5 toward rightangu lar relation with the adjacent walls, and this spreading movementof the walls causes opening or unfolding of the portions 24 and 25 ofthe flaps 23 toward positions in a common plane. As the end wall l5 andside wall |3 swing away from each other, the wall |5 draws the attachedportion 24 of one flap 23 in one direction while the wall |3 draws thesecuring portion 25 in an opposed direction, because of the connectiontherebetween provided by the panel 20. "The other flap 23 is similarlyacted upon by the walls |2 and I4 and the bottom panel l8. At the sametime that the flaps 23 are unfolded by the Walls and bottom panels, theydraw the panels I8 and 20 toward substantially the same plane by meansof the portions 25. It is, of course, obvious that the flaps 23 whenfully open or flat lie substantially in the plane of the bottom edges ofthe side and end walls, and in assuming that position swing the panels|8 and 20 about their connections with the side walls I2 and I3downwardly to close the bottom of the carton. As the panels I8 and 20approach each other in this movement, they also move laterally relativeto each other. The positions of the parts during the erection of thecarton are clearly shown in Figs. 1 and 2.

Before the free edges of the panels l8 and 20 reach the center line ofthe bottom, the tongues l9 and 2| projecting from such edges come intoengagement with each other, and because of the combined approaching andlateral movement of the panels l8 and 20, which of course is shared bythe tongues, push against each other, bending backwardly and upwardly,and simultaneously slide past each other.. Since each of the tongues l9and 2| in effect increases the width of its panel to more than half thewidth of the carton I0 as long as the carton is not opened to its fullwidth at the time of engagementof the tongues, the angle between thetongues l9 and 2| when. they come into engagement is such that neithertongue will slip beneath the other. Instead, as already stated, bothtongues are forced up and back. Thus the tongue 2| cannot jam in theangle betweenthe panel l8 and the adjacent portion 24, nor can thetongue l9 enter under the panel 20, as the tongues slide past eachother. The disposition of the tongue 2| adjacent the free end of thepanel 20, that is, the end which is not secured to the flap 23, aids inthis jam-avoiding action because of greater flexibility and resilienceof the parts, as fully explained hereinafter.

As the tongues move past each other, the tongue |9 moves intooverlapping relation with the panel 20 between the tongues 2| and 22,while the tongues 2| and 22 move into position overlapping the panel l8at each end of the tongue l9. As shown in Figs. 3 and 4, in thisposition of the parts the carton is in fully set up condition. It isalso locked in that position by the locking tongues l9 and 2| in theirmovement past each other during erection of the carton. The lookingedges 28 opposingly engage each other to hold the parts againstmovements reverse to those in the setting. up of the carton, or in otherwords, to prevent collapsing of the carton ID. This will be quite clearfrom Fig. 3. The resilience of the material and the bias resulting fromthe forming of the blank into the collapsed form of the carton tend tospring the parts back toward collapsed position. This collapsingtendency holds the locking edges 28 firmly engaged, and is checked bythat look. The locking edges, of course, also prevent collapse due tothe application of external forces tending to return it to its collapsedform. In the form illustrated collapse isalso resisted by the engagementof the side edges of panels l8 and 20 with end walls I4 and |5,respectively.

If the tongues l9 and 2| for any reason did not move into positionsoverlapping the panels 20 and I8 as explained above, it is obvious thatthe edges 28 would not be in looking engagement and the carton would besubject to collapse. This might result either from a tongue slippingbeneath the opposed panel and jamming against the flap 23 securedthereto, or by the tongues not being moved into proper locking positionwith their locking edges 28 opposingly engaged. These .diificultiesoften occur with prior constructions,

but are avoided in the carton of this invention.

The prevention of jamming by the present construction has already beenexplained. The carton of the present invention also avoids the seconddifficulty, failure to lock, because the structure positively assuresthat the locking edges 28 will be brought into locking engagement. Thestresses imposed by the tongues I9 and 2| on each other during theirsliding engagement as described above are, of course, relieved as theedges 28 pass each other, and the tongues react by flipping or snappingpast each other into the desired relation. This reaction due to theresilience of the carton material when added to the pull exerted by theflaps 23 on the panels l8 and 20 carrying the tongues results in ampleforce being applied to the panels and tongues to bring them into thedesired position to be locked by the edges 28. The disposition of thetongue 2| adjacent the free end of the panel 20 and'the perpendicularityof the edges 28 relative to the bottom edges of the side walls also aidin this positive locking action, as hereinafter pointed out.

Although the erection of the carton I0 and the action and movement ofthe parts have been described in something of a detailed, step-by-stepmanner, this has been done only in the interest of clearness. In actualuse, cartons embodying the invention are set up by a light, quick thrustor blow against one or both ends of the collapsed carton, and the partsmove into the described positions too quickly for the eye to follow.

It is an important feature of the invention that one of the lockingtongues is disposed adjacent the free end of its panel. Not beingstiffened and restrained by the attachment of the flap 23, as is thecase with the secured end of the panel, the free end is more flexibleand resilient. It will flex readily when the tongues l9 and 2| come intoengagement in the erecting movement of the carton. In the remote eventof the tongues interfering with each other, this ready flexing resultsin the tongue 2| yielding to the tongue l9 suificiently to overcome theinterference and prevent the tongues jamming against each other. In theusual event of no interference between the tongues, the additionalflexibility facilitates the bending of the tongues to prevent jammingunder the panels, as explained above. Further, upon disengagement of thetongues as they slide past each other, the snap action of the tongueswhich assures positive locking as previously described is enhanced byreaction of the free end of the panel upon release from its flexedcondition, in addition tothe resilient reaction of the tongue 2|.

Another important feature is the formation of the locking edges 28 sothat they are perpendicular to the bottom edges of the respective sidewalls, or in other words so that each edge 2!! lies in a plane normal tothe side walls. It will readily be appreciated that this formation ofthe locking edges permits instantaneous snapping of the tongues l9 and2i into the locking position as they disengage in the erecting movementof the carton, or in other words as the locking edges 28 move past eachother. The proportions and positions of the parts are such that thispoint is reached as the carton comes to fully erected condition. It istherefore unnecessary to strain and force the walls toward each otherafter they have reached their set up positions, as might be necessary ifthe tongues had the locking edges flaring from their junctions with thepanels. n the other hand, the tongues are not eased toward lockingposition by means of a gently angled or curved edge or edges, whichmight cause dissipation of the force of resilience of the tongues and soresult in the tongues failing to reach locking position.

Both of the features of construction and the resulting actions pointedout cooperate to assure a non-jamming and positive locking of eachcarton by a single, quick, and easy setting up operation.

It will be understood that the embodiment of the invention illustratedand described is exemplary, and that the invention is not limited tothis particular embodiment. Various modifications of and alterations inthe illustrative construction may be made without departing from theprinciples and spirit of thepresent invention. For example, the flap 23may be formed without the fold lines 26 and secured to the panels l8 and20, appropriate fold lines then being pro-- square, so that thearbitrary designations used are helpful in distinguishing one pair ofwalls from the other.

I claim:

1. A rectangular lock two pairs of opposed side walls and a bottomcomprising a pair of substantially rectangular panels each hinged on thebottom edge of a wall of one of said wall pairs and having a lengthsubstantially that of the carton and a width half that of the carton, alocking tongue projecting from the central portion of the free edge ofone of said panels, a locking edge on one end of said tongue lying in aplane normal to the walls of said one wall pair, a pair of tonguesprojecting from the free edge of the other panel and having the innerends thereof spaced apart a distance corresponding to the length of saidlooklocking tongue in extended condition of the bottom upon erection ofthe carton to prevent collapse thereof, the tongues having locking edgesbeing at least as long at their bases as at their free edges; a pair offlap each hinged on the bottom edge of a wall of the other wall pair andhaving a portion secured to one of said panels adjacent one end thereof,and a foldline in each connected panel and flap permitting upwardfolding thereof and extending along a line substantially bisecting thecorner angle between the walls on which said connected panel and flapare hinged, the secured end portion of said one panel being thatadjacent the locking edge of said looking tongue and the secured endportion of said other panel being that opposite the end portion adjacentsaid one of said pair of tongues having a locking edge.

2. A rectangular lock bottom carton having two pairs of opposed sidewalls and a bottom, said bottom comprising a pair of substantiallyrectangular panels each of substantially carton length and half thecarton width and hinged on the lower edge of a wall of one of said wallpairs,

bottom carton having I a pair of flaps each, hinged on the lower edge ofa wall of the other wall pair, a pair of tabs each hinged to one of saidflaps along a line substantially bisecting an adjacent corner angle ofthe carton and secured to an end portion of one of said panels, wherebythe carton may be erected from flattened condition with said bottomparts folded upwardly between said walls to erected condition with saidbottom parts extended to close the space defined by the walls and withthe free edges of said panels lying along one center line of the carton,a locking tongue projecting from the central portion of the free edge ofone of said panels and having a locking edge at the end thereof adjacentthe secured end of said one panel, and a pair of tongues projecting fromthe free edge of the other panel and having their inner ends spacedapart a distance corresponding to the length of said locking tongue, oneof said pair of tongues carried by said other panel having a lockingedge at its inner end, eachof said locking edges extending in a planenormal to the walls of said one wall pair, the tongues having saidlocking edges being adapted to yieldingly engage during erectingmovement of the carton to urge each other up wardly against movementbeneath a panel and each of said tongues having lockingedges being atleast as long at its base as at its free edge, and.

said locking edges being adapted to opposingly engage each other inerected condition of the carton to provide a lock substantially on saidcenter line but spaced from the transverse center line of the bottom ofthe carton to hold the carton against collapse.

LAWRENCE H. PHILLIPS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

